Manufacture of cellulose products.



I UNITED STATES PATENT OFFICE.

MAX FREMERY AND JOI-IANNES URBAN, OF OBERBRUCH, NEAR AAOlIEN, GERMANY.

MANUFACTURE OF CE LLULOSE PF KODUCTS.

SPECIFICATION forming part of Letters lPatent No. 705,748, dated July29, 1902.

Application filed May 5, 1900. Serial No. 15,643. (No specimens.)

"To all whom it may concern:

Be it known that we, MAX FREMERY, a subject of the King of Prussia,Emperor of Germany, and J OHANNES URBAN, a subject of the Emperor ofAustria-Hungary, both residing at Oberbruch, near Aachen, in the GermanEmpire, have invented certain new and useful Improvements in theManufacture of Cellulose Products; and we do hereby declarethe followingto be afull, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

The present invention consists in new and useful improvements in andrelating to the washing of cellulose products,such as threads, films,filaments, and the like obtained in an initially gelatinous state fromcellulose solutions. Such products are obtained, as is well known, bydissolving cellulose (with or withoutprevious treatment) in a suitablesolvent,

' such as solutions of cupro-ammonium or of chlorid of zinc, andsquirting such cellulose solution through fine holes or apertures orslits in the form of jets of the desired crosssection into a mediumprecipitating or coagulating cellulose-e. g., into a diluted acid oralcohol, common-salt solution, &c.thereby obtaining an initiallygelatinous or colloidal thread, film, or fiber of precipitatedcellulose. Such cellulose products are quite different from products ofcellulose with its original and natural porous condition, such as cottonyarn or hemp fiber, &c., and they contain after their formation parts ofthe cellulose solvent e. g., cupriferous or zinciferous combinations. Inour Letters Patent No. 661,214, dated November 6, 1900, we havedescribed a method of eliminating such impurities by washing theseproducts with water, causing the washing-water to slowly flow in smallportions or in a weak spray from above onto the spools on which the saidcellulose products are spooled, these spools being supported one overthe other. The reason for that method of operation was that we haddiscovered that by bringing such cellulose products suddenly intocontact with a great bulk of Water insoluble basic salts, such as zincoxychlorid, or insoluble metallic compounds, such as Ou(OH) readily formfrom the cellulose solvents, which basic salts or metallic compoundscannot be eliminated by further washing with water. The method ofwashing described in our Letters Patent, however, is only sufficient ifthe washing process be performed very carefully, so as to avoid theabove-mentioned formations or separations of insoluble basic salts ormetallic compounds; otherwise such a formation or separation will takeplace. In order to facilitate and to insure completeness of this washingprocess, we have found that it is important to add to the washing-watera substance which will prevent the formation or separation of insolublebasic salts or metallic compounds or convert the latter into solublesalts or compounds. Such substance may be chosen according to thechemical nature of the said separations and may be an acid-e. g.,sulfuric acid, acetic acid, and thelikeorasalt c. g., common salt. It awashing liquid of this kind be employed in the manner above mentioned,it rapidly and thoroughly penetrates by capillary action the cellulosemate rial, so that only small quantities of washing liquid arenecessary, without any risk of an undesirable formation of basic saltsbeing occasioned thereby, which is always liable to take place whenlarge quantities of clean water are employed.

Our improved process is therefore very inexpensive. Any traces of acidor salt washing solution that may have remained can be very easily andrapidly removed from the cellulose material by using only smallquantities of clean water by a washing operation afterward carried outin the same manner. In cases where acetic acid or any other volatileacid is employed a further washing with clean water can be dispensedwith, since the remaining acetic acid evaporates during the succeedingdrying without chemically deteriorating the cellulose articles.

In carrying out the present process we may employ, for example, onepart, by weight, of acetic acid in one thousand parts, by weight, ofwater. Such diluted acid is caused to flow by drops over the spools onwhich the cellulose threads are rolled up in the manner as described inour Patent No. 661,214 and with the same apparatus, only with the dif-ICO ference that instead of water we use the above-described diluteacid. 7

If the acid employed is not volatile and atfects objectionably thecellulose products during a contact for an elongated space of time,awashing with clean Water, as described in our Patent No. 661,214, mayfollow the said washing with dilute acid.

We claim as our invention 1. In the washing of cellulose productsresulting from the precipitation or coagulation of cellulose solutions,the method of facilitating and securing the eliminai ion of metalliccompound remaining Within the said cellulose products, which methodconsists in causing water containing a substance capable of convertingthe said metallic compounds into soluble salts to slowly flow from aboveonto the said products while coiled up, substantially as set forth.

2. In the washing of cellulose products resulting from the precipitationor coagulation of cellulose solutions, the method of facilitating andsecuring the elimination of metallic compound remaining within the saidcellulose products, which method consists in causing water containing asubstance capable of convertin g the said metallic compounds intosoluble salts to slowly flow from above onto the said products whilecoiled up and then causing pure water to likewise flow from above on thesaid products, substantially as set forth.

3. In the washing of cellulose products resulting from the precipitationor coagulation of cellulose solutions, the method of facilitating andsecuring the elimination of metallic compounds remaining within the saidcellulose products, Which method consists in cansing water containing anacid to slowly flow from above onto the said products while coiled up,substantially as set forth.

In testimony whereof we have affixed our signatures in presence of twowitnesses.

MAX FREMERY. JOHANNES URBAN.

Witnesses:

G. 'ScoTT, F. M. BRUNDAGE.

